Longitudinal Rates and Risk Factors for Adverse Birth Weight Among First Nations Pregnancies in Alberta.

OBJECTIVE

We wished to identify the prevalence, longitudinal trends, and associated risk factors for various birth weight categories by First Nations ethnicity in the province of Alberta.

METHODS

We performed a retrospective analysis of administrative data for the years 2000 to 2009 inclusive. Age-adjusted prevalence trends for high birth weight (HBW; > 4000g), very HBW (> 4500g), low birth weight (LBW; < 2500g), and very LBW (< 1500g) were compared via average annual percent change analyses. Logistic regression analysis was used to determine risk factors.

RESULTS

First Nations ethnicity was a significant independent predictor of HBW (OR 1.82 [95% CI 1.75, 1.89]), very HBW (OR 2.35 [95% CI 2.18, 2.52]), and very LBW (OR 1.35 [95% CI 1.23, 1.48]), but not of LBW (OR 0.98 [95% CI 0.93, 1.03]). However, HBW prevalence decreased and other birth weight categories remained stable over time in First Nations populations. Gestational diabetes and maternal weight ≥ 91 kg were potentially manageable risk factors for HBW. Potentially manageable risk factors for LBW included pre-gestational renal disease, hypertension, and maternal weight ≤ 45 kg, as well as smoking, illicit drug dependence, and alcohol consumption.

CONCLUSION

Although HBW, very HBW, and very LBW remain more common in Alberta First Nations populations than in the general population, their prevalence is not increasing.